1. Field of the Invention
The subject invention relates to an apparatus having an improved black background to enable enhanced visual inspection for particulate matter in parenteral drugs. The black background also can be used to improve accuracy of any optical measuring device using photocells or any automatic vision system where an object is surface illuminated and inspected against a dark background for contrast.
2. Description of the Prior Art
Parenteral drugs are subject to carefully controlled manufacturing processees and post-manufacturing inspection processees to ensure suitability for their intended purpose. One such post-manufacturing process involves a visual inspection for particulates suspended in the drug. These particulates can originate in the drug manufacturing process, in the process of manufacturing vials, ampules or syringes or in the filling process of such vials, ampules or syringes. Particulates that might exist typically are small and can be virtually any shape or color.
The prior art typically relies upon visual inspection of a statistically significant sample of containers (e.g. vials, ampules or syringes) filled with carefully identified batches of parenteral drugs and their containers. Visual observation of unacceptable particulates in the parenteral drugs typically will result in an entire batch being subject to more extensive inspection and the entire batch may be discarded if the initial tests are accurate. A bad batch could generate a subsequent inquiry to identify the source of the particulate in the tightly controlled manufacturing process.
The typical prior art particulate inspection apparatus includes a black inspection background and a white inspection background. The vial, ampule or syringe is placed between the inspector and the black inspection background to identify any light colored particles that may be suspended in the drug. The container is then moved between the inspector the white inspection background to enable the inspector to see dark particulate matter that may be suspended in the drug. The inspector often may be aided by a magnifying glass or other focusing means positioned between the inspector and the container of parenteral drugs being inspected.
The accuracy and reliability of the prior art particulate inspection apparatus depends in part upon the whiteness and blackness of the backgrounds used for the inspection. For example, dirt or dust on the white or black background may appear as a particle suspended in a parenteral drug. Scratches or other damage that will inevitably occur during use also are visually apparent through the parenteral drug, and may be perceived as particulate matter that is actually not present. Similarly, over time, the reflectivity and color of the black or white surfaces can change. Any or all of the above deficiencies in the blackness and/or whiteness of the respective backgrounds can cause a higher-than-necessary reject rate of drugs, with very substantial cost penalties to the pharmaceutical manufacturer. More particularly, the pharmaceutical manufacturer will have already invested significant amounts of time and money in an entire batch of drugs and a corresponding batch of ampules, vials or syringes when the suspected particulate matter is observed. The entire batch will then have to be isolated and either discarded or subjected to much more extensive testing and inspection.
Accordingly, it is an object of the subject invention to provide an apparatus to achieve enhanced particulate inspection.
It is another object of the subject invention to provide a particulate inspection apparatus having a black background that will retain a high degree of blackness for a very long time.
It is a further object of the subject invention to provide a black background for particulate inspection apparatus that is not significantly affected by dust or dirt, that is not easily damaged and that is not affected by changes in coloration or reflectivity over time.